Combustion tube



FIG. 1 is a rear elevational view of a combustion tube;

FIG. 2 is a right side elevational view thereof; a left side elevational view is identical as the right side elevational view;

FIG. 3 is a front elevational view thereof;

FIG. 4 is an enlarged detail taken from FIG. 3 thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a rear perspective view thereof. 

CLAIM The ornamental design for a combustion tube, as shown and described. 